Digital strategy to compensate offset currents into DC-DC Dual Active Bridge converter simulations

DC-DC Dual Active Bridge converters (DAB) can prospectively play an important role both in Medium Voltage and Low Voltage DC grids development, allowing interconnections at different voltage levels. Depending on converter topology and power electronics control strategy, heavy offset currents can appear, causing saturation, power loss increase and power electronics overload. This work is geared towards an analog-domain control strategy to avoid offset currents generation in DAB converters simulations, to validate models both for software and real time tests. Analog and discrete-domain converter control simulations have been compared to assess the DC offsets origin and develop a digital strategy to avoid them. The proposed strategy, validated also with Control Hardware in The Loop (CHIL) Real-Time (RT) tests, has been successfully implemented in the analog-domain simulations. It proved to be able to compensate the offset currents occurring in some configurations. The desired DC offset currents compensation is obtained with simple and fast integration in existing converter controls schemes, avoiding significant modifications and preserving the validity of original simulative model.